Chemical liquid discharge mechanism, liquid processing apparatus, chemical liquid discharge method, and storage medium

ABSTRACT

Disclosed is a chemical liquid discharge mechanism. The mechanism includes: a storage portion including a chemical liquid storage space; a diluent supply port opened to supply a diluent for reducing a viscosity of the chemical liquid to the storage space; a vertex flow forming portion that forms vortex flows in the diluent and the chemical liquid by supplying a fluid to the storage space to stir the diluent and the chemical liquid; and a liquid discharge port opened to an upper side of the diluent supply port in the storage space such that, by the supply of the diluent, the diluent and the chemical liquid flow into the liquid discharge port to be discharged from the storage space. Thus, the viscosity of the waste liquid discharged from the liquid discharge port may be reduced, and thus, it is not necessary to largely set the inclination of the liquid discharge path.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/795,213, filed on Jul. 9, 2015, which claims priority from JapanesePatent Application No. 2014-143453, filed on Jul. 11, 2014, all of whichare incorporated herein in their entireties by reference.

TECHNICAL FIELD

The present disclosure relates to a chemical liquid discharge mechanismfor use in a liquid processing apparatus that performs a liquidprocessing, a liquid processing apparatus including the chemical liquiddischarge mechanism, a chemical liquid discharge method, and a storagemedium including a computer program.

BACKGROUND

In a semiconductor device manufacturing process, various chemicalliquids such as, for example, a resist, is supplied to a semiconductorwafer (hereinafter, referred to as a “wafer”) as a substrate, using acoating apparatus that is one of liquid processing apparatuses. Thechemical liquid, scattered or overflowing from the wafer, flows to thebottom portion of, for example, a cup that forms the coating apparatusand is installed to surround the wafer. Then, the chemical liquid flows,as waste liquid, in a liquid discharge pipe connected to the bottomportion of the cup to be removed. The liquid discharge pipe is installedto be inclined, for example, downwardly so that the chemical liquidnaturally flows by weight. Japanese Patent Laid-Open Publication No.2012-33886 discloses a coating apparatus the cup and the liquiddischarge pipe as described above.

In some cases, a chemical liquid having a relatively high viscosity maybe used as the chemical liquid. In order to ensure that the chemicalliquid flows in the liquid discharge pipe even if the viscosity of thechemical liquid is so high, the liquid discharge pipe is installed at arelatively large angle with respect to a horizontal plane. However, whenthe liquid discharge pipe is installed in this way, the height occupiedby the liquid discharge pipe at the lower side of the cup is increased,which makes it difficult to miniaturize the coating apparatus.

While descriptions have been made on the waste liquid from the cup, insome cases, the coating apparatus may supply a chemical liquid to aplace other than the cup, and the chemical liquid becomes the wasteliquid, as will be described in detail in the description of exemplaryembodiments of the present disclosure. A liquid discharge pipeconfigured to allow the waste liquid to flow therein also has anincreased height due to a reason that is the same as the liquiddischarge pipe connected to the cup, which may disturb miniaturizationof the coating apparatus. The problems encountered in discharging thechemical liquid having a high viscosity as described above is notlimited to an apparatus that performs a processing on a wafer like theaforementioned coating apparatus, i.e. an apparatus that performs aso-called pre-processing of a semiconductor manufacturing process. In apost-processing of the semiconductor manufacturing process, a wafer iscut to form a chip, then a chemical liquid such as, for example, aliquid resin is supplied to the chip, and the chemical liquid is curedto form a package that covers the chip. In general, the chemical liquidfor forming a package also has a high viscosity. Therefore, when aliquid discharge pipe for discharging the chemical liquid is installed,the height may be increased like the liquid discharge pipe that isconnected to the cup as described above.

Japanese Patent Laid-Open Publication No. 2012-33886 discloses a systemthat is provided with the liquid discharge path as described above and atank that collects waste liquid, but does not disclose a means forsolving the problems as described above. Japanese Patent Laid-OpenPublication No. H5-7674 discloses a technique for mixing mixing-targetmaterials within a tank by forming vortex flows within the tank, butdoes not disclose the problems as described above. The mixing targetmaterials flow in a pipe connected to the lower side of the tank and isdischarged from the tank by opening/closing a valve installed in thepipe, which requires burdens in opening/closing the valve andmanufacturing costs due to the installation of the valve.

SUMMARY

A chemical liquid discharge mechanism of the present disclosureincludes: a storage portion including a storage space where a chemicalliquid is stored; a diluent supply port opened so as to supply a diluentfor reducing a viscosity of the chemical liquid to the storage space; avertex flow forming portion configured to form vortex flows in thediluent and the chemical liquid by supplying a fluid to the storagespace so as to stir the diluent and the chemical liquid; and a liquiddischarge port opened to an upper side of the diluent supply port in thestorage space such that the diluent and the chemical liquid are causedto flow into the liquid discharge port to be discharged from the storagespace by the supply of the diluent after stirring of the diluent and thechemical liquid is terminated.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical sectional side view of a resist coating apparatusto which a chemical liquid discharge mechanism of the present disclosureis applied.

FIG. 2 is a plan view of the resist coating apparatus.

FIG. 3 is a perspective view of a liquid discharge system provided inthe resist coating apparatus.

FIG. 4 is a vertical sectional side view of a resist liquid storageportion of a cup liquid discharge mechanism that forms the liquiddischarge system.

FIG. 5 is a horizontal sectional plan view of the resist liquid storageportion.

FIG. 6 is an explanatory view illustrating a state where the resistliquid is discharged from the resist liquid storage portion.

FIG. 7 is an explanatory view illustrating a state where in which theresist liquid is discharged from the resist liquid storage portion.

FIG. 8 is an explanatory view illustrating a state where in which theresist liquid is discharged from the resist liquid storage portion.

FIG. 9 is a vertical sectional perspective view of a nozzle bath thatforms the liquid discharge system.

FIG. 10 is a side view of the nozzle bath.

FIG. 11 is a vertical sectional side view illustrating a liquid storageportion for pre-dispensing which forms the nozzle bath, and the gasdischarge/liquid discharge tank.

FIG. 12 a vertical sectional side view illustrating a liquid storageportion for dummy dispensing which forms the nozzle bath and a gasdischarge/liquid discharge tank that forms the liquid discharge system.

FIG. 13 is a timing chart of processings performed in the resist coatingapparatus.

FIG. 14 is an explanatory view illustrating a state where the resistliquid is discharged from the liquid storage portion for pre-dispensing.

FIG. 15 is an explanatory view illustrating a state where the resistliquid is discharged from the liquid storage portion for pre-dispensing.

FIG. 16 is an explanatory view illustrating a state where the resistliquid is discharged from the liquid storage portion for pre-dispensing.

FIG. 17 is a timing chart of the dummy dispensing.

FIG. 18 is a vertical sectional side view illustrating anotherconfiguration of the resist liquid storage portion of the cup liquiddischarge mechanism.

FIG. 19 is a vertical sectional perspective view illustrating anotherconfiguration of the resist liquid storage portion.

FIG. 20 is a vertical sectional perspective view illustrating anotherconfiguration of the resist liquid storage portion.

FIG. 21 is a vertical sectional perspective view illustrating anotherconfiguration of the resist liquid storage portion.

FIG. 22 is a horizontal sectional perspective view illustrating anotherconfiguration of the resist liquid storage portion.

FIG. 23 is a horizontal sectional plan view illustrating anotherconfiguration of the resist liquid storage portion.

FIG. 24 is a vertical sectional perspective view illustrating anotherconfiguration of the resist liquid storage portion.

FIG. 25 is a vertical sectional perspective view illustrating anotherconfiguration of the resist liquid storage portion.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawing, which form a part hereof. The illustrativeembodiments described in the detailed description, drawing, and claimsare not meant to be limiting. Other embodiments may be utilized, andother changes may be made without departing from the spirit or scope ofthe subject matter presented here.

The present disclosure has been made in consideration of the problemsdescribed above, and an object of the present disclosure is to provide atechnique that may reduce a height occupied a chemical liquid dischargepath in a chemical liquid discharge mechanism for discharging a chemicalliquid having a relatively high viscosity.

According to an exemplary embodiment of the present disclosure, achemical liquid discharge mechanism includes: a storage portionincluding a storage space where a chemical liquid is stored; a diluentsupply port opened so as to supply a diluent for reducing a viscosity ofthe chemical liquid to the storage space; a vertex flow forming portionconfigured to form vortex flows in the diluent and the chemical liquidby supplying a fluid to the storage space so as to stir the diluent andthe chemical liquid; and a liquid discharge port opened to an upper sideof the diluent supply port in the storage space such that the diluentand the chemical liquid are caused to flow into the liquid dischargeport to be discharged from the storage space by the supply of thediluent after stirring of the diluent and the chemical liquid isterminated.

In the chemical liquid discharge mechanism described above, the storagespace has a circular shape in plan view, and the vortex flow formingportion is configured by the diluent supply port that supplies thediluent in a tangential direction of the storage space in plan view.

In the chemical liquid discharge mechanism described above, the diluentsupply port is configured by a first diluent supply port and a seconddiluent supply port. Each of the first diluent supply port and thesecond diluent supply force supplies the diluent in the tangentialdirection of the storage space so that vortex flows are formed inreverse directions in the storage space in plan view. The diluent isalternately supplied from the first diluent supply port and the seconddiluent supply port.

In the chemical liquid discharge mechanism described above, the diluentis supplied from the diluent supply port such that a processing periodin which the diluent is supplied at a first flow rate that forms thevortex flows and a waiting period in which the diluent is supplied at asecond flow rate lower than the first flow rate are repeated.

In the chemical liquid discharge mechanism described above, the storagespace has a circular shape in plan view, and the vortex flow formingportion is configured by a gas supply port that supplies a gas in atangential direction of the storage space in plan view.

In the chemical liquid discharge mechanism described above, the vortexflow forming portion is configured by the gas supply port and thediluent supply port. Formation of vortex flows by supplying the diluentand the gas and formation of vortex flows by supplying the gas withoutsupplying the diluent are alternately and repeatedly performed.

The chemical liquid discharge mechanism described above furtherincludes: a collision member configured to collide with agglomeratesformed by coagulation of components of the chemical liquid. Thecollision member is installed in the storage space so as to crush theagglomerates flowing to turn around the storage space by the vortexflows.

In the chemical liquid discharge mechanism described above, thecollision member is a net-like member.

The chemical liquid discharge mechanism described above further includesa restraint member configured to restrain a liquid flow of the chemicalliquid and the diluent in the storage space. The restraint member isinstalled in the storage space.

In the chemical liquid discharge mechanism described above, therestraint member includes a shaft member provided at a central portionof the storage space having the circular shape in plan view along aheight direction of the storage space.

According to another exemplary embodiment of the present disclosure, aliquid processing apparatus includes: a mounting unit configured tomount a substrate thereon; a chemical liquid supply unit configured tosupply a chemical liquid to the substrate mounted on the mounting unitso as to perform a processing; a cup configured to surround thesubstrate mounted on the mounting unit; and a chemical liquid dischargemechanism described above. The storage portion of the chemical liquiddischarge mechanism is installed at a lower side of the cup such thatthe chemical liquid is discharged from a liquid discharge path providedin a bottom portion of the cup to the storage portion of the storageportion.

According to another exemplary embodiment of the present disclosure, aliquid processing apparatus includes: a mounting unit configured tomount a substrate thereon; a chemical liquid supply unit configured tosupply a chemical liquid to the substrate mounted on the mounting unitso as to perform a processing; and a chemical liquid discharge mechanismdescribed above. The storage portion of the chemical liquid dischargemechanism forms a liquid receiving portion that receives the chemicalliquid supplied from the chemical liquid supply unit at the outside ofthe substrate.

In the liquid processing apparatus described above, the diluent is asolvent of the chemical liquid. The liquid receiving portion isconfigured by a first chemical liquid discharge mechanism and a secondchemical liquid discharge mechanism. A gas discharge mechanism isprovided to evacuate the storage space from a liquid discharge port foronly one chemical liquid discharge mechanism among the first chemicalliquid discharge mechanism and the second chemical liquid dischargemechanism, and an upper side of the storage space in another chemicalliquid discharge mechanism among the first chemical liquid dischargemechanism and the second chemical liquid discharge mechanism forms awaiting region of a solvent atmosphere where the chemical liquid supplyunit waits.

According to another exemplary embodiment of the present disclosure, achemical liquid discharge method includes: storing a chemical liquid ina chemical liquid storage space provided in a storage portion; supplyinga diluent for reducing a viscosity of the chemical liquid from a diluentsupply port opened to the storage space to the storage space; formingvortex flows in the diluent and the chemical liquid by supplying a fluidto the storage space so as to stir the diluent and the chemical liquid;and after stirring of the diluent and the chemical liquid is terminated,causing, by the supply of the diluent, the diluent and the chemicalliquid to flow into a liquid discharge port opened to an upper side ofthe diluent supply port to be discharged from the storage space.

In the chemical liquid discharge method described above, the storagespace has a circular shape in plan view, and the forming the vortexflows includes supplying the diluent from the diluent supply port in atangential direction of the storage space in plan view.

In the chemical liquid discharge method described above, the forming thevortex flows includes alternately supplying the diluent from a firstsupply port and a second supply port that form the diluent supply portso that the vortex flows are formed in reverse directions.

In the chemical liquid discharge method described above, the forming thevortex flows includes: supplying the diluent from the diluent supplyport at a first flow rate forming the vortex flows, and supplying thediluent from the diluent supply port at second flow rate lower than thefirst flow rate, which are alternately and repeatedly performed.

In the chemical liquid discharge method described above, the storagespace has a circular shape in plan view, and the forming the vortexflows includes supplying a gas in a tangential direction of the storagespace in plan view.

In the chemical liquid discharge method described above, the forming thevortex flows includes: forming vortex flows by supplying the gas and thediluent in the tangential direction of the storage space in plan view,and forming vortex flows by supplying the gas without supplying thediluent, which are repeatedly performed.

According to still another exemplary embodiment of the presentdisclosure, there is provided a computer-readable storage medium storinga computer executable program that, when executed, performs the chemicalliquid discharge method described above using a chemical liquiddischarge mechanism.

According to the present disclosure, vortex flows are formed in thestorage space so that the chemical liquid and the diluent are stirred,and after the stirring, the chemical liquid and the diluent aredischarged from the liquid discharge port at the upper side of thediluent supply port by the supply of the diluent. In this way, theviscosity of the chemical liquid flowing into the liquid discharge portmay be sufficiently reduced. Thus, it is not necessary to largely setthe inclination of the liquid discharge path connected to the liquiddischarge port. Accordingly, since the height occupied by the liquiddischarge path may be suppressed, the height of the apparatus to whichthe present disclosure is applied may be suppressed.

Descriptions will be made on a resist coating apparatus 1 as anexemplary embodiment of a liquid processing apparatus including achemical liquid discharge mechanism of the present disclosure withreference to the vertical sectional side view of FIG. 1 and a plan viewof FIG. 2. The resist coating apparatus 1 supplies a resist liquid to awafer W as a substrate so as to form a resist film, in which the resistcoating apparatus 1 is configured by processing sections 1A, 1B, anozzle mechanism 1C, and a liquid discharge system 4.

Descriptions will be made on a processing section 1A. The processingsection 1A is provided with a spin chuck 11 serving as a substratemounting unit that vacuum-sucks a rear central portion of the wafer W soas to maintain the wafer W horizontally. In the figures, referencenumeral 12 indicates a rotary mechanism connected to the spin chuck 11via a shaft 13 so as to rotate the spin chuck 11 about a vertical axis.In the figures, reference numeral 14 indicates an annular platesurrounding the shaft 13, reference numeral 15 in the figures indicateslifting pins vertically penetrating the annular plates 14. Referencenumeral 16 in the figures indicates a lifting mechanism configured tomove up and down the lifting pins 15. The lifting pins 15 and the spinchuck 11 perform delivery of wafers W with conveyance mechanism 17provided in the outside the resist coating apparatus 1 as illustrated inFIG. 2.

A top-opened cup 2 is installed to surround the lateral side of thewafer W mounted on the spin chuck 11. The cup 2 receives waste liquidscattered or overflowing from the wafer W and guides the waste liquid tothe bottom of the cup 2. In the figures, reference numeral 21 indicatesa guide member that forms the cup 2. The guide member 21 is providedoutside the annular plate 14. In order to guide the waste liquid, theguide member 21 is installed along the circumference of the wafer W andis formed in a mountain shape in vertical sectional view. The guidemember 21 is provided with a rear cleaning nozzle 22 configured to ejectthinner to the rear surface of the wafer W.

The lower side of the cup 2 is formed as a liquid receiving portion 23in a recessed shape in vertical sectional view. The liquid receivingportion 23 is provided in an annular shape so as to surround the shaft13 to form the bottom portion of the cup 2. In the bottom surface of theliquid receiving portion 23, a liquid discharge port 24 is opened toremove the waste liquid that has flown to the liquid receiving portion23. To the liquid discharge port 24, one end of a liquid discharge pipe25 is connected from the outside of the cup 2. The other end of theliquid discharge pipe 25 extends to the lower side of the cup 2 and isconnected to a cup liquid discharge mechanism 41A that forms the liquiddischarge system 4. The cup liquid discharge mechanism 41A will bedescribed later. In the figure, reference numeral 26 indicates a gasdischarge pipe installed to vertically penetrate the liquid receivingportion 23. While the liquid receiving portion 23 is provided with twogas discharge pipes, FIG. 1 illustrates only one gas discharge pipe. Thegas discharge pipe 26 is connected to a gas discharge damper (notillustrated) to evacuate the inside of the cup 2 at a desired exhaustamount.

In addition, the processing section 1A is provided with a film removingthinner nozzle 31, in which the film removing thinner nozzle 31 locallysupplies the thinner to the peripheral edge of a wafer W having a resistfilm formed thereon so as to remove the resist film of the peripheraledge. In the figures, reference numeral 32 indicates a nozzle arm, towhich the film removing thinner nozzle 31 is connected. Referencenumeral 33 in FIG. 2 indicates a moving mechanism configured to movemoving the nozzle arm 32 between a position above the peripheral edge ofthe wafer W mounted on the spin chuck and the outside of the cup 2.Reference numeral 34 indicates a guide for moving the moving mechanism33 thereon. The processing section 1B is configured to be the same asthe processing section 1A described above, except that the liquiddischarge pipe 25 of the cup 2 is connected to the cup liquid dischargemechanism 41B (to be described below) that forms the liquid dischargesystem 4.

Subsequently, descriptions will be made on the nozzle mechanism 1C. Thenozzle mechanism 1C includes four resist liquid nozzles 35 and onethinner nozzle 36. The resist liquid nozzles 35 are connected todifferent resist liquid supply sources via resist liquid supply pipes,respectively. In addition, the resist liquid nozzles 35 supply differentresist liquids to a wafer W. Illustration of the resist liquid supplypipes and the resist liquid supply sources is omitted. By a control unit10 to be described later, a resist liquid nozzle 35 to be used isselected according to a lot of wafers W.

The resist liquid nozzles 35 and the thinner nozzle 36 are arranged in arow in a horizontal direction in the nozzle arm 37. Each resist liquidnozzle 35 and the thinner nozzle 36 respectively supply a resist liquidand thinner vertically downwardly. The thinner is supplied to the waferW before the resist liquid is supplied, and is used for performing apre-wetting processing that improves the wettability of the wafer W forthe resist liquid. The resist liquid and the thinner are supplied to thecentral portion of the wafer W, and coated over the entire wafer W byso-called spin coating that causes the resist liquid and the thinner tobe spread by a centrifugal force generated by the rotation of the waferW.

In FIG. 2, reference numeral 38 indicates a moving mechanism that movesthe nozzle arm 37. By the moving mechanism 38, the nozzle arm 37 may bemoved in the arrangement direction of the resist liquid nozzles 35 andthe thinner nozzle 36 and in the vertical direction. Consequently, eachresist liquid nozzle 35 and the thinner nozzle 36 may be moved betweenthe inside of a nozzle bath (described later) that forms the liquiddischarge system 4 and the central portion of the wafer W mounted on thespin chuck 11. In FIG. 2, reference numeral 39 indicates a guide formoving the nozzle arm 37 thereon in the horizontal direction. The nozzlemechanism 1C described above are commonly used by the processingsections 1A and 1B, processings on the wafer W are individuallyperformed in the processing sections 1A and 1B.

Subsequently, descriptions will be made on the liquid discharge system4. The resist liquid supplied from each resist liquid nozzle 35 has arelatively high viscosity, and the liquid discharge system 4 has afunction of diluting the resist liquid that have become waste liquid soas to reduce the viscosity thereof, and discharging the resist liquidfrom the resist coating apparatus 1. FIG. 3 illustrates a perspectiveview of the liquid discharge system 4. The liquid discharge system 4includes a thinner supply mechanism 40 (see FIG. 2), cup liquiddischarge mechanisms 41A, 41B, a nozzle bath 51, and a gasdischarge/liquid discharge tank 61. Each of the cup liquid dischargemechanisms 41A, 41B and the nozzle bath 51 forms a chemical liquiddischarge mechanism of the present disclosure.

Descriptions will be made on the thinner supply mechanism 40. Thethinner supply mechanism 40 is connected to each of the cup liquiddischarge mechanisms 41A, 41B and the nozzle bath 51 through a separatethinner supply pipe 50 so as to supply the thinner to each thinnersupply pipe 50. The thinner is a solvent of the resist liquid and alsoserves as a diluent that dilutes the resist liquids to reduce theviscosity of the resist liquid. The thinner supply amount for each ofthe thinner supply pipes 50 is independently adjusted according to acontrol signal from the control unit 10.

Next, descriptions will be made on the cup liquid discharge mechanisms41A, 41B. The cup liquid discharge mechanisms 41A, 41B are formed byresist liquid storage portions 42 that are provided below the cup 2 ofthe processing section 1A and below the cup 2 of the processing section1B, respectively. Except for the places where the resist liquid storageportions 42 are provided, the cup liquid discharge mechanisms 41A, 41Bare configured to be equal to each other. Hereinafter, descriptions willbe made on the cup liquid discharge mechanism 41A as a representativethereof.

FIGS. 4 and 5 illustrate a vertical sectional side view and a horizontalsectional plan view of the resist liquid storage portion 42 of the cupliquid discharge mechanism 41A, respectively. The resist liquid storageportion 42 includes a storage space 43 therein, the downstream end ofthe liquid discharge pipe 25 of the cup 2 is opened at the top side ofthe storage space 43, and the resist liquid that has flown in the liquidreceiving portion 23 as the waste liquid flows into the storage space 43from the liquid discharge pipe 25. The storage space 43 is formed in acircular shape in plan view as illustrated in FIG. 5, and a shaft member44 directed to the top side from the lower end of the storage space 43is provided at the center of the storage space 43. As will be describedbelow, vortex flows (swirling flows) are formed within the storage space43 by the thinner so that the thinner and the resist liquid are stirred.However, since the flowing velocity of the liquid is slowed at thecenter of the storage space 43 in plan view as compared with that in theperipheral edge, the degree of stirring is low at the center of thestorage space 43. For that reason, the center is provided with the shaftmember 44 so as to obtain a constitution where the resist liquid and thethinner are not supplied, thereby increasing the degree of stirring.That is, the shaft member 44 is configured as a restraint member thatretrains the flow of the resist liquid and the thinner in the storagespace 43.

At the lower end portion of the storage space 43, a thinner supply port45 is opened laterally so as to supply the thinner along the bottomsurface of the storage space 43. As illustrated in FIG. 5, the thinnersupply port 45 is formed to be opened in a tangential direction of thestorage space 43 in plan view to be capable of forming vortex flows. Inthe figure, reference numeral 46 indicates a thinner flow path, and isformed to be connected to the thinner supply port 45 in the resistliquid storage portion 42. The thinner supply pipe 50 is connected tothe flow path 46. In addition, at the upper side of the thinner supplyport 45 in the storage space 43, a liquid discharge port 47 is openedtoward the outside of the storage space 43 to be inclined downwardly,and the upstream end of the liquid discharge pipe 48 is connected to theliquid discharge port 47 from the outside of the resist liquid storageportion 42. The downstream end of the liquid discharge pipe 48 isinclined downwardly and connected to the gas discharge/liquid dischargetank 61.

Here, summary of the operation of the cup liquid discharge mechanism 41Awill be described with reference to FIGS. 6 to 8. In FIGS. 6 to 8,thinner is indicated by reference numeral 20, resist liquid is indicatedby reference numeral 30, and a mixed liquid of the thinner 20 and theresist liquid 30 (diluted resist liquid) is indicated by referencenumeral 39. In this example, it is assumed that the thinner 20 is alwayssupplied from the thinner supply mechanism 40 to the storage space 43,and first, the thinner 20 is being supplied at 100 mL/min, for example.In this state, since the flow rate of the supplied thinner 20 isrelatively small, no vortex flow is formed in the storage space 43. Theexcessive thinner 20 supplied to the storage space 43 flows into theliquid discharge pipe 48 from the liquid discharge port 47. As describedabove, the liquid discharge pipe 48 is inclined downwardly and theviscosity of the thinner 20 is low, the thinner that has flown into theliquid discharge pipe 48 flows to the downstream in the liquid dischargepipe 48 by weight to be removed from the storage space 43.

In addition, in the processing section 1A, when the coating of theresist liquid 30 is performed on the wafer W and the resist liquid 30overflowing or scattered from the wafer W is supplied from the cup 2 tothe storage space 43 and stored in the storage space 43 (FIG. 6), theflow rate of the thinner 20 supplied from the thinner supply mechanism40 to the storage space 43 increases to, for example, 400 mL/min. Thethinner 20, ejected from the supply port 45 to the storage space 43 atthe relatively large flow rate as described above, flows along thelateral circumferential surface of the storage space 43 in thecircumferential direction of the storage space 43 in plan view, therebyforming the vortex flows (FIG. 7). FIGS. 7 and 5 indicate the directionof the vortex flows by arrows.

In the storage space 43, the resist liquid 30 is stirred by the thinner20 that forms the vortex flows as described above, and the thinner 20forming the vortex flows and the resist liquid 30 are rapidly mixed witheach other. That is, the resist liquid 30 stored in the storage space 43is diluted by the thinner 20, and the vortex flows are formed by themixed liquid 39. In addition, since the thinner 20 is continuouslysupplied from the lower side of the storage space 43, the vortex flowsof the mixed liquid 39 are swept upwardly by the thinner 20 and flowinto the liquid discharge pipe 48 from the liquid discharge port 47.Since the mixed liquid 39 includes the thinner 20, its viscosity islower than the viscosity of the resist liquid 30. For that reason, themixed liquid 39 that has flown into the liquid discharge pipe 48 isflows to the downstream side of the liquid discharge pipe 48 by weightlike the thinner 20, thereby being removed from the resist liquidstorage portion 42. After the supply of the resist liquid 30 to thewafer W and the supply of the resist liquid 30 to the storage space 43are stopped, the flow rate of the thinner 20 is reduced again to 100mL/min and the formation of vortex flows is stopped (FIG. 8). The timingwhen the flow rate of the thinner is changed will be further describedbelow with reference to an example.

Supplying the thinner 20 at a relatively low flow rate when the supplyof the resist liquid 30 with respect to the storage space 43 is stoppedis to suppress the unnecessary consumption of the thinner 20 and toprevent the storage space 43 from being clogged as the resist liquid 30is dried and solidified when the resist liquid 30 remains in the storagespace 43. That is, even if the resist liquid 30 remains in the storagespace 43 after the formation of the vortex flow is stopped, the thinneris supplied next until the supply amount of the thinner to the storagespace 43 is increased so as to form the vortex flows in the storagespace 43. Therefore, the storage space 43 is not dried and the fluidityof the resist liquid 30 is maintained. In addition, when the vortexflows are formed next, the resist liquid 30 is mixed with the thinner 20and removed from the storage space 43.

In this way, the supply of the thinner at a relatively large flow rate(first flow rate) and the supply of the thinner at a relatively smallflow rate (second flow rate) are repeatedly performed so as to allow theresist liquid 30 in the storage space 43 to be more reliably discharged.The flow rate of the thinner is not limited to those in the exampledescribed above. In addition, in the case where the flow rate of thinneris changed between the first flow rate capable of forming the vortexflow and the second flow rate smaller than the second flow rate asdisclosed above, the second flow rate may also be a flow rate capable offorming the vortex flow.

Returning to the descriptions of the configuration of the liquiddischarge system 4, the nozzle bath 51 serving as a liquid receivingportion will be described. As illustrated in FIGS. 1 to 3, the nozzlebath 51 is installed to be held between the cups 2 of the processingsections 1A, 1B in the outside of the cups 2, and is formed in asubstantially rectangular parallelepiped shape. Like the cup liquiddischarge mechanisms 41A, 41B, the nozzle bath 51 includes a storagespace 43 in which vortex flows are formed by the thinner so that thethinner and the resist liquid are stirred, and the stirred and dilutedresist liquid is discharged from the storage space 43. The nozzle bath51 is provided with three storage spaces 43, to each of which the resistliquid is ejected from one of the resist liquid nozzles 35.

One of the storage spaces 43 is a space to which the resist liquid isejected, for example, when the maintenance of the resist coatingapparatus 1 is performed, and is used for performing dummy dispensingthat discharges the resist liquid staying within the resist liquidnozzles 35 and resist liquid supply pipes (not illustrated) connected tothe upstream side of the resist liquid nozzles 35. The dummy dispensingis an operation performed as being instructed from the control unit 10to be described later by, for example, the user of the resist coatingapparatus 1. The dummy dispensing is performed so as to check, forexample, the ejection state of the resist liquid from the resist liquidnozzles 35, the interrupted state of the liquid from the resist liquidnozzles 35 after the ejection of the resist liquid, and thecontamination of the resist liquid nozzles 35.

The other two storage spaces 43 are provided so as to performpre-dispensing that discharges the old resist liquid within the resistliquid nozzles 35 just before the resist liquid nozzles 35 supply theresist liquid to a wafer W. One storage space 43 for performing thepre-dispensing is commonly used by two resist liquid nozzles 35.

For the convenience of description, the storage space for dummydispensing will be indicated by reference numeral 43A, and the storagespaces for pre-dispensing will be indicated by reference numeral 43B,and the descriptions on the nozzle bath 51 will be continued withreference to FIGS. 9 and 10. FIG. 9 is a vertical sectional perspectiveview of the nozzle bath 51 and FIG. 10 is a front view of the nozzlebath 51. In connection with the storage spaces 43A, 43B, the locationsconfigured to be the same as those in the storage spaces 43 of the cupliquid discharge mechanisms 41A, 41B will be given the same referencenumerals as those in the storage spaces 43 and the descriptions thereofwill be omitted.

In the nozzle bath 51, the storage spaces 43A, 43B, 43B are provided ina row in the horizontal direction, in which the arranged direction ofthe storage spaces 43A, 43B, 43B are the same as the arranged directionof the resist liquid nozzles 35 and the thinner nozzle 36. At the upperside of one storage space 43B, two circular openings 52 are provide tocommunicate with the storage space 43B and opened to the upper side ofthe nozzle bath 51. That is, the nozzle bath 51 is provided fouropenings 52, and each resist liquid nozzle 35 waits in the state whereits tip end (lower end) is introduced into one of the openings 52. Inaddition, the nozzle bath 51 is provided with a circular opening 53opened to the upper side of the nozzle bath 51. When the resist liquidnozzles 35 are waiting within the openings 52, the thinner nozzle 36waits in the state where its tip end is introduced into the opening 53.FIGS. 9 and 10 illustrate the resist liquid nozzles 35 and the thinnernozzle 36 which are waiting within the openings 52, 53, respectively.

In addition, a circular opening 54 is provided at the upper side of thestorage space 43A to communicate with the storage space 43A and to beopened to the upper side of the nozzle bath 51. The dummy dispensing isperformed in the following manner: one of the resist liquid nozzles 35ejects the resist liquid to the storage space 43A through the opening 54at an upper side position of the opening 54. In order to preventscattering of the resist liquid ejected from the position, the diameterof the opening 54 is formed to be larger than those of the openings 52,53.

As in the storage spaces 43 of the cup liquid discharge mechanisms 41A,41B described above, each of the storage spaces 43A, 43B, 43B isprovided with a shaft member 44, a thinner supply port 45, and a liquiddischarge port 47. In addition, flow paths 46, which are respectivelyconnected to the thinner supply ports 45, are formed in the nozzle bath51. The flow paths 46 are connected with the thinner supply pipes 50,respectively, so that the thinner may be supplied to each of the storagespaces 43A, 43B, 43B from the thinner supply mechanism 40.

At the front side of the nozzle bath 51, a flow path forming member 55is provided (see FIGS. 1 to 3). FIG. 11 illustrates a vertical sectionalside view of the flow path forming member 55 and one storage space 43B.Descriptions will be continued with reference to FIG. 11. The liquiddischarge port 47 of the storage space 43B is connected to one end ofthe liquid discharge path 56 formed in the flow path forming member 55,and the other end of the liquid discharge path 56 is inclineddownwardly. The other end of the liquid discharge path 56 is connectedwith one end of the liquid discharge pipe 57, and the other end of theliquid discharge pipe 57 is formed vertically downwardly to be connectedto the gas discharge/liquid discharge tank 61. The thinner and thediluted resist liquid, introduced into the liquid discharge port 47 fromthe storage space 43B, automatically flow through the liquid dischargepath 56 and the liquid discharge pipe 57 to the downstream by weight,and flow into the gas discharge/liquid discharge tank 61.

FIG. 12 illustrates a vertical sectional side view of the storage space43A. As illustrated in FIG. 12, the liquid discharge port 47 of thestorage space 43A is connected with one end of the liquid discharge pipe58. The other end of the liquid discharge pipe 58 is inclined downwardlyand then curved vertically downwardly to be connected to the gasdischarge/liquid discharge tank 61. As the liquid discharge pipe 58 isformed in this way, the thinner and the diluted resist liquid introducedinto the liquid discharge port 47 from the storage space 43 aautomatically flow through the liquid discharge pipe 58 to thedownstream by weight and flow into the gas discharge/liquid dischargetank 61, like the thinner and the diluted resist liquid introduced intothe liquid discharge path 56 of the storage space 43B.

Next, descriptions will be made on the gas discharge/liquid dischargetank 61 with reference to FIGS. 11 and 12. FIGS. 11 and 12 illustratevertical sectional side views of the gas discharge/liquid discharge tank61 at different positions, respectively. The gas discharge/liquiddischarge tank 61 is provided with a space 62 therein. The downstreamend of the liquid discharge pipe 58, connected to the storage space 43Afor dummy dispensing, is opened in this space 62 (FIG. 12). In addition,the downstream ends of the liquid discharge pipes 48 of the cup liquiddischarge mechanisms 41A, 41B are connected to lateral sides of the gasdischarge/liquid discharge tank 61, and the inside of each of the liquiddischarge pipes 48 and the space 62 communicate with each other throughan opening 63 formed in the gas discharge/liquid discharge tank 61.While the opening 63 is provided for each of the cup liquid dischargemechanisms 41A, 41B, the figure illustrates only the opening 63connected to the cup liquid discharge mechanism 41A.

At a lateral side of the gas discharge/liquid discharge tank 61, aliquid discharge port 64 is formed and opened to a side surface of thelower end of the space 62. The bottom surface within the gasdischarge/liquid discharge tank 61 is formed as an inclined surface. Thewaste liquid of the diluted resist liquid and the thinner, which haveflown to the bottom surface of the gas discharge/liquid discharge tank61 from the openings 63 connected to the cup liquid discharge mechanism41A, 41B, and from the liquid discharge pipes 58 connected to the nozzlebath 51, respectively, are guided to the liquid discharge port 64. Inaddition, the liquid discharge port 64 is connected with one end of aliquid discharge pipe 65 from the outside of the gas discharge/liquiddischarge tank 61 (see, e.g., FIGS. 1 to 3), and the other end of theliquid discharge pipe 65 extends to be inclined downwardly and connectedto a liquid discharge path of a factory where the resist coatingapparatus 1 is installed. The waste liquid, guided to the liquiddischarge port 64 from the bottom surface within the gasdischarge/liquid discharge tank 61, automatically flows through theliquid discharge pipe 65 to the downstream by weight and then flows intothe liquid discharge path of the factory to be removed.

In addition, one end of a gas discharge path 66 is opened to the space62 of the gas discharge/liquid discharge tank 61, and the other end ofthe gas discharge path 66 is connected to a gas discharge mechanism 68through a gas discharge pipe 67, and the space 62 is always evacuated bythe gas discharge mechanism 68. In FIGS. 11 and 12, the discharge gasflows formed in each portion by the evacuation of the gas dischargemechanism 68 are indicated using dotted line arrows.

In addition, as illustrated in FIG. 11, the other end of the liquiddischarge pipe 57 connected to the storage space 43B for free dispensingis installed to be directed toward the lower side of the space 62. Abottomed cylinder member 69 is installed to enclose the other end of theliquid discharge pipe 57, and the upper end of the cylinder member 69 isin contact with the ceiling within the gas discharge/liquid dischargetank 61. In the lateral portion of the cylinder member 69, liquiddischarge ports 71 are formed at a position higher than the lower end ofthe liquid discharge pipe 57. In the inside of the cylinder member 69,the lower side of the liquid discharge ports 71 is formed as a liquidstorage portion 72. The waste liquid flowing in the liquid dischargepipe 57 (i e thinner and diluted resist liquid (mixed liquid)) is storedin the liquid storage portion 72, and swept to the outside of thecylinder member 69 by the waste liquid which continuously flows from theliquid discharge pipe 57. Then, the waste liquid drops to the bottomsurface of the inside of the gas discharge/liquid discharge tank 61.Then, the waste liquid is guided by the inclined bottom surface to theliquid discharge port 64 and removed from the gas discharge/liquiddischarge tank 61 together with the waste liquid flowing from theopenings 63 connected to the cup liquid discharge mechanisms 41A, 41Band the liquid discharge pipe 58 connected to the storage space 43A.

Descriptions will be made on the reason why the liquid storage portion72 is formed in the gas discharge/liquid discharge tank 61. The storagespaces 43A, 43B of the nozzle bath 51 are always supplied with thinnersimilarly to the storage spaces of the cup liquid discharge mechanisms41A, 41B, for example. Specifically, similarly to the flow rate of thethinner supplied to the storage spaces 43, the flow rate of the thinnersupplied to the storage spaces 43A, 43B is switched between 100 mL/minand 400 mL/min, for example. As a result, a state in which vortex flowsare formed and a state in which no vortex flow is formed are switched.As the thinner is always supplied to the storage space 43B of the nozzlebath 51 in this way, waste liquid always flows in the liquid storageportion 72 illustrated in FIG. 11 so that the waste liquid is in thestored state.

Accordingly, even if the space 62 of the gas discharge/liquid dischargetank 61 is evacuated by the gas discharge mechanism 68, the lower end ofthe liquid discharge pipe 57 is sealed by the stored waste liquid sothat the inside of the storage space 43B that forms the first chemicalliquid discharge mechanism connected to the liquid discharge pipe 57,and the opening 52 in which the resist liquid nozzle 35 waits are notevacuated. For that reason, the inside of the opening 52 that becomes anozzle waiting region is always maintained as a thinner atmosphere bythe thinner supplied to the storage space 43B. Thus, while the resistliquid nozzle 35 is waiting, the resist liquid is prevented from beingdried within the resist liquid nozzles 35 and thus, the resist liquidnozzle 35 is prevented from being clogged. Meanwhile, the inside of thestorage space 43A and the opening 53 in the nozzle bath 51, which formthe second chemical liquid discharge mechanism, are evacuated throughthe liquid discharge pipe 58 by the evacuation of the space 62 by thegas discharge mechanism 68 (see FIG. 12). Accordingly, the thinneratmosphere may be suppressed from being diffused from the opening 53 tothe outside of the nozzle bath 51, and as a result, the perimeter of thewafer W may be suppressed from being contaminated by the thinneratmosphere.

As illustrated in FIG. 1, the resist coating apparatus 1 is providedwith a control unit 10 which is a computer. In the control unit 10, forexample, a program stored in a storage medium such as, for example, aflexible disc, a compact disc, a hard disc, a magneto-optical (MO) disc,or a memory card, is installed. The installed program includes commands(respective steps) combined to transmit a control signal to each unit ofthe resist coating apparatus 1 so as to control the operations thereof.Specifically, the operations such as, for example, the rotation of thewafer W by the rotary mechanism 12 via the spin chuck 11, the movementsof the resist liquid nozzles 35 and the thinner nozzle 36, the switchingof the flow rate of thinner supplied from each thinner supply pipe 50 bythe thinner supply mechanism 40, are controlled by the program.

Next, descriptions will be made on an operation of the resist coatingapparatus 1 at the time of processing the wafer W. FIG. 13 is a timechart for describing the operation. A period, in which a resist liquidis supplied from the resist liquid nozzles 35 during a series ofprocessings on the wafer W, is indicated by a solid line bar graph. Inthis chart, a period, in which the flow rate of the thinner supplied toeach of the storage space 43 of the cup liquid discharge mechanism 41Aand the storage space 43B of the nozzle bath 51 is 400 mL/min, isconsidered a vortex flow forming period, and each bar graph is indicatedto correspond with the resist liquid supply period. In addition,reference will be properly made to FIGS. 14 to 16 illustrating thestates of the storage space 43B. In FIGS. 14 to 16, the thinner isindicated by reference numeral 20, the resist liquid is indicated byreference numeral 30, and the mixed liquid of the thinner 20 and theresist liquid 30 (diluted resist liquid) is indicated by referencenumeral 39 as in FIGS. 6 to 8.

First, it is assumed that the resist liquid nozzles 35 and the thinnernozzle 36 wait within the openings 53 and the opening 54, respectively,and the thinner 20 is being supplied to each of the storage spaces 43A,43B of the nozzle bath 51 and the storage spaces 43 of the cup liquiddischarge mechanisms 41A, 41B at a flow rate of 100 mL/min FIG. 11described above illustrates the storage space 43B at this time. In thisstate, a leading wafer W of a lot is carried into, for example, the cup2 of the processing section 1A and the central portion of the rearsurface thereof is held on the spin chuck 11. The old resist liquid 30included in the resist liquid nozzle 35 is supplied from the resistliquid nozzle 35 set to the lot, to the storage space 43B, andpre-dispensing is initiated (time t1 in the chart) (FIG. 14).

Simultaneously when the supply of the resist liquid 30 from the resistliquid nozzle 35 is stopped and the pre-dispensing is terminated, theflow rate of the thinner supplied to the storage space 43B, to which theresist liquid 30 has been supplied, increases and becomes 400 mL/min(time t2). As a result, as in the case where the flow rate of thethinner 20 supplied to the storage space 43 becomes 400 mL/min asdescribed above with reference to FIG. 7, vortex flows are formed in thestorage space 43B. By the vortex flows, the thinner 20 and the resistliquid 30 are stirred and the resist liquid 30 is diluted, therebyforming the mixed liquid 39 which flows into the liquid discharge port47 as waste liquid. After flowing into the liquid discharge port 47, themixed liquid 39 is supplied to the gas discharge/liquid discharge tank61 as described above with reference to FIG. 11, and then removed fromthe resist coating apparatus 1. In this way, while the discharge of themixed liquid 39 proceeds, the thinner nozzle 36 and the resist liquidnozzle 35 are moved to a position above the wafer W carried into theprocessing section 1A (FIG. 15).

In addition, the thinner nozzle 36 is positioned above the centralportion of the wafer W and supplies the thinner to the central portionof the wafer W (time t3). The wafer W is rotated, and thus, the thinneris spread over the entire surface of the wafer W, so that a pre-wetprocessing is performed. Meanwhile, in the storage space 43B, thestirring of the thinner 20 and the resist liquid 30 and the discharge ofthe mixed liquid 39 thereof are continued. When the supply of thethinner from the thinner nozzle 36 to the wafer W is stopped and thepre-wet processing is terminated (time t4), the resist liquid nozzle 35that has performed the pre-dispensing is positioned above the centralportion of the wafer W and supplies the resist liquid to the centralportion of the wafer W (time t5). The resist liquid is spread to theperipheral edge of the wafer by the centrifugal force generated by therotation of the wafer W so that the resist liquid is coated over theentire surface of the wafer W. The resist liquid 30 scattered oroverflowing from the wafer W is guide to the cup 2 and supplied to andstored in the storage space 43 of the cup liquid discharge mechanism41A, as described above with reference to FIG. 6.

While the supply of the resist liquid 30 to the wafer W is continued, inthe nozzle bath 51, the flow rate of the thinner supplied to the storagespace 43B is reduced to 100 mL/min, and the formation of vortex flow isstopped (time t6). Thereafter, the flow rate of the thinner 20 suppliedto the storage space 43 of the cup liquid discharge mechanism 41A isincreased to be 400 mL/min (time t7), and vortex flows are formed asdescribed above with reference to FIG. 7 so that the thinner 20 and theresist liquid 30 are stirred. As described above with reference to FIGS.11 and 12, the mixed liquid 39, formed as the resist liquid 30 isdiluted by the thinner 20, flows from the storage 43 into the liquiddischarge port 47 to be supplied to the gas discharge/liquid dischargetank 61 as waste liquid and to be removed from the resist coatingapparatus 1. Thereafter, the supply of the resist liquid to the wafer Wis stopped (time t8), and the supply of the resist liquid 30 to thestorage space 43 of the cup liquid discharge mechanism 41A is alsostopped. Thereafter, the flow rate of the thinner supplied to thestorage space 43 is reduced to 100 mL/min (time t9).

The resist liquid nozzle 35 and the thinner nozzle 36 return to theopenings 52, 53 of the nozzle bath 51 and wait therein, respectively. Inthe cup 2 of the processing section 1A, the rotation of the wafer W iscontinued and the dry of the coated resist liquid proceeds, therebyforming a resist film. Then, the thinner is supplied to the rear surfaceof the rotating wafer W from the rear cleaning nozzle 22 so that thecleaning of the rear surface is initiated (time t10), and subsequently,the supply of thinner from the film removing thinner nozzle 31 to theperipheral edge of the wafer W is initiated (time t11) so that theresist film is locally removed in the peripheral edge of the wafer W.Then, the supply of the thinner from the film removing thinner nozzle 31is stopped (time t12), and subsequently, the supply of the thinner fromthe rear cleaning nozzle 22 is stopped (time t13). Even after the supplyof the thinner is stopped, the rotation of the wafer W is continued sothat the dry of the thinner supplied to the wafer W proceeds.

Meanwhile, for example, a subsequent wafer W is carried into the cup 2of the processing section 1B. In the cup 2 of the processing section 1A,the rotation of the processed wafer W is stopped and the wafer W iscarried out from the cup 2 while the pre-dispensing is initiated in thenozzle bath 51 so as to process the wafer W of the processing section 1B(time t14). That is, the same operation as that performed at time t1 isperformed. Thereafter, the same operations as the those performed attime t2 to time t14 as described above are sequentially performed at thesame timing as in the case where the wafer W is processed in theprocessing section 1A. As such, the wafer W carried into the processingsection 1B is subjected to the same processings as the wafer W carriedinto the processing section 1A while, in the nozzle bath 51 and the cupliquid discharge mechanism 41B corresponding to the cup 2 of theprocessing section 1B, formation of vortex flows by the thinner 20,formation of mixed liquid 39 by dilution of the resist liquid 30, anddischarge of the mixed liquid 39 are performed in parallel with theprocessings of the wafer W. Thereafter, the wafers W are alternatelycarried into the processing section 1A and the processing section 1B,and the processings on the wafers W and the discharge of the resistliquid from the coating apparatus 1 are performed in the same way.

Next, descriptions will be made on a case where the dummy dispensing isperformed while focusing on a difference between the case where thedummy dispensing is performed and the case where the pre-dispensing isperformed, with reference to FIG. 17 that is a timing chart representingthe periods where a resist liquid is ejected and the period where thevortex flows are formed, similarly to FIG. 13. For example, the userdesignates a resist liquid nozzle 35 to perform the dummy dispensing anda timing of performing the dummy dispensing by the control unit 10. Atthe designated timing, a resist liquid nozzle 35 standing by within theopening 52 is moved upward from the opening 52, and the designatedresist liquid nozzle 35 is moved to a position where the resist liquidnozzle 35 is capable of ejecting the resist liquid to the opening 54 ofthe nozzle bath 51. This position is located above the opening 54 suchthat the nozzle bath 51, the resist liquid nozzle 35, and the thinnernozzle 36 do not interfere with each other. FIG. 12 illustrates theresist liquid nozzle 35 moved to this position. When the resist liquidnozzle 34 designated in this way is moved to the upper side of theopening 54, the flow rate of the thinner supplied to the storage space43A is 100 mL/min, and no vortex flow is formed in the storage space43A.

Thereafter, the resist liquid is ejected from the designated resistliquid nozzle 35 (time s1 in the chart), and the old resist liquidwithin the resist liquid nozzle 35 and the resist liquid supply pipeconnected to the resist liquid nozzle 35 is stored in the storage space43A of the nozzle bath 51 through the opening 54. To the inside of theresist liquid nozzle 35 and the supply pipe from which the old resistliquid was discharged, a new resist liquid is supplied from the supplysource from the resist liquid.

Thereafter, the flow rate of the thinner supplied to the storage space43A is increased to 400 mL/min, and vortex flows are formed in thestorage space 43A as in the case where the supplied thinner is increasedin the above-described storage spaces 43, 43B. Then, the resist liquidis mixed with the thinner and discharged from the storage space 43A(time s2). When all the old resist liquid within the resist liquidnozzle 35 and the resist liquid supply pipe is discharged and replacedby the new resist liquid, the ejection of the resist liquid is stopped(time s3), and then, the flow rate of the thinner is reduced to 100mL/min so that the formation of the vortex flows is stopped (time s4).Subsequently, after the replacement of the resist liquid, as anoperation for determining whether the ejection is normally performed,the ejection of the resist liquid is initiated again (time s5), andthen, the flow rate of the thinner supplied to the storage space 43Abecomes 400 mL/min again so that vortex flows are formed (time s6). Whena predetermined amount of the resist liquid is ejected, the ejection ofthe resist liquid is stopped (time s7), and then, the flow rate of thethinner is reduced to 100 mL/min and the formation of the vortex flowsis stopped (time s8).

With the resist coating apparatus 1, the resist liquid supplied from thecups 2 or the resist liquid nozzles 35 is stored in each of the storagespaces 43, 43A, 43B of the cup liquid discharge mechanisms 41A, 41B andthe nozzle bath 51. In addition, in each of the storage spaces 43, 43A,43B, thinner is supplied to form vortex flows, and the resist liquid isstirred by the supply of the thinner and diluted by the thinner so thatthe viscosity of the resist liquid is reduced. Since the thinner issupplied from the lower side of the storage space 43, the diluted resistliquid is swept to the liquid discharge ports 47 at the upper side ofthe storage spaces 43, 43A, 43B, and removed from the liquid dischargeports 47. As the resist liquid having the reduced viscosity is suppliedto the liquid discharge ports 47 in this way, even if the inclinationwith respect to the horizontal plane is not largely set for each of theliquid discharge pipes 48, 58, 65, the liquid discharge paths 56, andthe gas discharge, and the bottom surface within liquid discharge tank61 at the downstream side of the liquid discharge ports 47, the resistliquid may naturally flow according to the inclination to be discharged.Accordingly, it is possible to prevent the enlargement of the resistcoating apparatus 1.

Next, descriptions will be made on another exemplary configuration ofthe cup liquid discharge mechanism 41A, while focusing on a differencebetween the present example and the preceding example. FIG. 18illustrates an example in which the cup liquid discharge mechanism 41Ais provided with an air supply port 81. Similarly to the thinner supplyport 45, the air supply port 81 is formed to be opened in the inner wallof the resist liquid storage portion 42 in the tangential direction ofthe storage space 43 in plan view. The air supply port 81 ejects airalong the bottom surface of the storage space 43. In the figure,reference numeral 82 indicates an air supply path formed in the resistliquid storage portion 42. Reference numeral 83 indicates an air supplysource that supplies air to the air supply port 81 through the airsupply path. In the figure, air bubbles are indicated by referencenumeral 84.

When air is supplied from the air supply port 81 in a state where theresist liquid and the thinner supplied from the thinner supply port 45are stored in the storage space 43, vortex flows may be formed in thethinner and the resist liquid stored in the storage space 43 so as toperform stirring even in the state where the supply of the thinner fromthe thinner supply port 45 is stopped. In this example, the direction ofthe vortex flows formed by the air ejected from the air supply port 81are the same as the direction of the vortex flows formed by the thinnerejected from the thinner supply port 45. For that reason, when the airis supplied from the air supply port 81 in parallel with supplying thethinner from the thinner supply port 45 as described above, vortex flowshaving a higher flow rate may be formed in the storage space 43 so thatthe stirring of the thinner and the resist liquid may be performed morereliably.

Descriptions will be made on a processing example using the cup liquiddischarge mechanism 41A illustrated in FIG. 18. In the processingexample illustrated in the chart of FIG. 13 described above, when theperiod, indicated as a period in which the flow rate of the ejectedthinner is 100 mL/min, is referred to as a waiting period and theperiod, indicated as a period in which the flow rate of the thinner is400 mL/min, is referred to as the processing period, the thinner and theair are supplied together to the storage space 43 so as to form vortexflows. In addition, in the waiting period, only the air is ejected inthe state where the ejection of the thinner is stopped so as to formvortex flows in the thinner stored in the storage space 43. That is, inrepeatedly processing wafers W in the cup 2 of the processing section1A, the formation of vortex flows by the thinner and the air and theformation of vortex flows only by the air are alternately and repeatedlyperformed. By performing the processings in this way, the resistremaining in the storage space and the thinner are stirred in thewaiting period so that it is possible to prevent the storage space 43from being clogged by the dry and solidification of the resist liquiddescribed above more reliably. In addition, since the ejection of thethinner is stopped in the waiting period, the use of thinner may bereduced and thus, the cost reduction of processing may be attained.

However, in the processing period, the thinner may be supplied at a flowrate that is capable of forming vortex flows, or the thinner may besupplied at a flow rate that does not form vortex flows so that vortexflows may be formed by the action of the supplied air. In such a case,for example, when the thinner is supplied to the storage space 43 afterstopping the formation of vortex flows, the mixed liquid of the stirredthinner and resist liquid is swept to the liquid discharge port 49 to beremoved from the storage space 43. That is, the formation of vortexflows is not limited to that performed by a liquid, but may be performedby a gas. That is, the formation of vortex flows may be performed by afluid.

The contents of the resist liquid may coagulate in the resist liquid toform agglomerates which are hardly mixed with the thinner. Accordingly,the storage space 43 of the cup liquid discharge mechanism 41Aillustrated in FIG. 19 is provided with a collision member 85 so thatthe agglomerates collide against the collision member 85 to be crushed.The collision member 85 has an erected plate shape, and is formed of anet that is installed to extend from the shaft member 44 to the innerwall of the resist liquid storage portion 42 and has a plurality ofholes in its surface direction. When vortex flows are formed, theagglomerates ride the vortex flows to flow in the circumferentialdirection of the storage space 43 in plan view. In addition, theagglomerates collide against the net to be crushed and pulverized, andescape the meshes of the net. The agglomerates pulverized in this mannerare mixed with the thinner and discharged from the storage space 43through the liquid discharge port 47. In addition, in the cup liquiddischarge mechanism 41A of FIG. 19, the position of the liquid dischargeport 47 in the circumferential direction of the storage space 43 and theposition of the thinner flow path 46 are different from those in each ofthe above-described examples, but vortex flows are formed as in each ofthe above-described examples.

The collision member 85 is not limited to the case where it is installedto be erected as illustrated in FIG. 19, but may be installed to extendin the horizontal direction at the lower side of the liquid dischargeport 47, as illustrated in FIG. 20. As described above, since vortexflows are directed upward, the agglomerates of the resist liquid collideagainst the collision member 85 to be crushed and pulverized whileflowing along the vortex flows to be directed upward in the storagespace 43, and are mixed with the thinner to be discharged from thestorage space 43. By installing the collision member 85 as illustratedin FIGS. 19 and 20, the resist liquid and the thinner may be stirredmore reliably to reduce the viscosity of the resist liquid.

FIGS. 21 and 22 are a vertical sectional side view and a horizontalsectional plan view of still another configuration example of the cupliquid discharge mechanism 41A, respectively. In the cup liquiddischarge mechanism 41A, a thinner supply port 86 is formed in additionto the thinner supply port 45. The thinner supply port 86 is configuredto be the same as the thinner supply port 45 except that the openingposition in the circumferential direction of the storage space 43 isdifferent from that of the thinner supply port 45. That is, the thinnersupply port 86 may form vortex flows by supplying the thinner to thestorage space, similarly to the thinner supply port 45. In FIG. 22, theflows of the thinner supplied from the respective thinner supply ports45, 86 are indicated by arrows, in which the thinner supplied from thethinner supply port 45 and the thinner supplied from the thinner supplyport 86 flow in the same direction around the storage space 43 to formthe vortex flows in the same direction. In addition, the air supply port81 illustrated in FIG. 18 are opened similarly to the thinner supplyport 86 in plan view, for example.

In FIG. 21, reference numeral 87 indicates a thinner flow path that isconnected to the thinner supply port 86 in which the thinner flow path87 is connected to the thinner supply mechanism 40 through the thinnersupply pipe 50, similarly to the flow path 46 connected to the thinnersupply port 45. For example, when the flow rate of the thinner ejectedfrom the thinner supply port 45 becomes a first flow rate which isrelatively high, the flow rate of the thinner ejected from the thinnersupply port 86 also becomes the first flow rate so that vortex flows areformed in the storage space 43. For example, when the flow rate of thethinner supplied from the thinner supply port 45 becomes a second flowrate which is relatively low, the flow rate of the thinner supplied fromthe thinner supply port 86 also becomes the second flow rate so thatformation of vortex flows is stopped. By forming a plurality of thinnersupply ports capable of forming vortex flows, the flowing velocity offormed vortex flows may be increased, which allows the stirring ofthinner and resist liquid to be performed more reliably.

In the cup liquid discharge mechanism 41A, the thinner supply port 86may be formed as illustrated in FIG. 23. In FIG. 23, the flow of thethinner ejected from the thinner supply port 45 is indicated by solidline arrows, and the flow of thinner ejected from the thinner supplyport 86 is indicated by dotted line arrows, in which the thinner ejectedfrom the thinner supply port 45 and the thinner ejected from the thinnersupply port 86 flow in reverse directions around the storage space 43.When the thinner is ejected from the thinner supply port 45 at a flowrate that is capable of forming vortex flows, the ejection of thethinner from the thinner supply port 86 is not performed. On thecontrary, when the thinner is ejected from the thinner supply port 86 ata flow rate that is capable of forming vortex flows, the ejection of thethinner from the thinner supply port 45 is not performed. That is, thethinner is alternately supplied from the thinner supply ports 45, 86 sothat vortex flows are formed in the reverse directions. Morespecifically, in the timing chart of FIG. 13, in the vortex flow formingperiod in cup liquid discharge mechanism 41A from time t7 to time t9,the direction of the vortex flows is changed one or more times.Consequently, turbulent flows are generated in the storage space 43 sothat the stirring effects of the thinner and the resist liquid can beimproved.

FIG. 24 illustrates still another exemplary configuration of the cupliquid discharge mechanism 41A. In this example, an erected cylindermember 91 is installed to enclose the shaft member 44 and to berotatable about the axis of the shaft member 44. From the cylindermember 91, four erected plates radially extend toward the peripheraledge of the storage space 43, in which each of the plates is formed as avane member 92. The vane members 92 are pushed by the thinner suppliedfrom the thinner supply port 45 to be rotated in the circumferentialdirection of the storage space 43, thereby more reliably forming vortexflows in the storage space 43. Consequently, the stirring of the thinnerand the resist liquid in the storage space 43 can be performed morereliably.

FIG. 25 illustrates yet another exemplary configuration of the cupliquid discharge mechanism 41A. In this example, a plate-shaped member93 is provided on the peripheral edge within the storage space 43. Theplate-shaped member 93 encloses the shaft member 44 and is formedspirally from the lower side of the storage space 43 toward the upperside of the storage space 43. FIG. 25 illustrates a vertical sectionalview, in which the plate-shaped member 93 is partially cut away. Whenthe thinner is supplied to the storage space 43, the plate-shaped member93 guides the thinner and the diluted resist liquid, thereby formingvortex flows more reliably. That is, the plate-shaped member 93 isformed as a restraint member that restrains liquid flow in the storagespace 43 together with the shaft member 44, and is provided so as toimprove stirring effects.

Descriptions will be made on yet another cup liquid discharge mechanism41A. For example, a heater is installed around the storage space 43 soas to heat the storage space 43, the power supplied to the heater iscontrolled according to a control signal from the control unit 100. Thatis, the temperature of the heater is changed based on the controlsignal, and the control signal that controls the power supplied to theheater so as to control the heater is used as a temperature controlsignal. In addition, according to a control signal output from thecontrol unit 100 to the thinner supply mechanism 40, the flow rate ofthe thinner from the thinner supply mechanism 40 is changed, forexample, as in each of the examples described above. When a controlsignal for changing the flow rate of the thinner is used as a thinnersupply signal, the temperature control signal is output to besynchronized with the output of the thinner supply signal, and a controlof the power supplied to the heater is performed.

More specifically, the control unit 100 outputs a thinner supply signalso that the flow rate supplied from the thinner supply mechanism 40 ischanged from 100 mL/min to 400 mL/min, and at the same time, the controlunit 100 outputs a temperature control signal so that the temperature ofthe heater is raised to be 80° C., for example. The temperature of thethinner supplied from the thinner supply mechanism 40 to the storagespace 43 is lower than the temperature of the heater (80° C.), forexample, 23° C. The thinner supplied to the storage space 43 and turningin the storage space 43 is heated by the heater so that the temperatureof the thinner is raised to about 40° C., for example. When thetemperature is raised in this manner, the dissolution rate of the resistliquid in relation to the thinner in the thinner storage space 43 isincreased, and stirring is rapidly performed. Thereafter, the controlunit 100 outputs a thinner supply signal so that the flow rate of thethinner supplied from the thinner supply mechanism 40 is changed from400 mL/min to 100 mL/min, and at the same time, the control unit 100outputs a temperature control signal so that the temperature of theheater is lowered to a predetermined temperature lower than 80° C.Instead of employing the configuration in which the thinner may beheated in the storage space 43 this way storage space 43, aconfiguration in which the thinner may be heated in the thinner supplymechanism 40 may be employed so that the temperature of the thinnersupplied to the storage space 43 becomes, for example, 40° C., inadvance.

The respective examples described above as exemplary configurations andprocessings of the cup liquid discharge mechanism 41A may be combinedwith each other. In addition, each example described with reference tothe configurations to the cup liquid discharge mechanism 41A may also beapplied to the cup liquid discharge mechanism 41B and the nozzle bath51. Although descriptions have been made on the liquid processingapparatus that supplies a resist liquid to a wafer as a chemical liquid,the chemical liquid is not limited to the resist liquid. Even in a casewhere, for example, polyimide for forming an insulating film is suppliedto a wafer, the viscosity of the chemical liquid is relatively high.Thus, the configuration of the present disclosure is also available insuch a case. In addition, the present disclosure is not limited to anapplication to an apparatus that performs a processing on a wafer W, butis applicable to other liquid processing apparatuses for semiconductormanufacture. More specifically, the present disclosure is alsoapplicable to a liquid processing apparatus that supplies a chemicalliquid for forming a package to a chip formed by cutting a wafer W, asdescribed in the background section above. Further, as long as thestirred liquid may be discharged from the storage space 43 by supplyinga diluent, the liquid discharge port 47 may not be opened to a lateralside of the storage space 42 as described above. For example, the liquiddischarge port 47 may be opened toward the upper side from the storagespace 42.

From the foregoing, it will be appreciated that various embodiments ofthe present disclosure have been described herein for purposes ofillustration, and that various modifications may be made withoutdeparting from the scope and spirit of the present disclosure.Accordingly, the various embodiments disclosed herein are not intendedto be limiting, with the true scope and spirit being indicated by thefollowing claims.

What is claimed is:
 1. A chemical liquid discharge mechanism comprising:a storage portion including a storage space having a circular shape in aplan view where a chemical liquid is stored; a vortex flow formingportion including a diluent supply port opened to a lower end of thestorage space and configured to supply a diluent for reducing aviscosity of the chemical liquid to the storage space by forming vortexflows in the diluent and the chemical liquid so as to stir the diluentand the chemical liquid; a liquid discharge port opened to an upper endof the storage space such that, by the supply of the diluent afterstirring of the diluent and the chemical liquid is terminated, thediluent and the chemical liquid flow into the liquid discharge port tobe discharged from the storage space; and a shaft member configured torestrain a liquid flow of the chemical liquid and the diluent in thestorage space and provided at a central portion of the storage spacehaving the circular shape in plan view and extended from a bottom of thestorage space along a height direction of the storage space; and acollision member extending laterally from the shaft member toward aninner wall of the storage portion and configured to divide the storagespace in the up-down direction, wherein the top end of the shaft memberis positioned lower than a top end of the liquid discharge port and thecollision member is positioned lower than a bottom end of the liquiddischarge port.
 2. The chemical liquid discharge mechanism of claim 1,wherein the diluent supply port supplies the diluent in a tangentialdirection of the storage space in the plan view.
 3. The chemical liquiddischarge mechanism of claim 1, wherein the shaft member is formed to bewider toward the end as it goes downward.
 4. The chemical liquiddischarge mechanism of claim 1, wherein the width of the storage spacein a vertical cross-sectional view is formed to be narrower toward thebottom of the storage space.
 5. The chemical liquid discharge mechanismof claim 1, wherein a chemical liquid supply port configured to supplychemical liquid to the storage space is opened along the extendingdirection of the shaft member above the shaft member.
 6. The chemicalliquid discharge mechanism of claim 1, wherein the collision member isconfigured to collide with agglomerates formed by coagulation ofcomponents of the chemical liquid so as to crush the agglomerates, andprovided with a plurality of penetrating holes, each of the penetratingholes being opened in the up-down direction such that the diluent andthe chemical liquid flows through the holes.